This invention relates generally to medical devices, and more particularly to a device for debriding, aspirating, and draining an abscess present in a human or veterinary patient.
A variety of locations within the body of a human or veterinary patient are subject to developing an abscess after the occurrence of infection or contamination at such locations. Contamination can result from structural changes or damage to tissues in the body caused by injury or surgery, or can result from structural irregularities arising naturally within the body. Abscesses often develop in an existing tract or passage within the body, such as in mucus glands, for example, rectal mucus glands. An abscess can perhaps most simply be considered as a sac containing bacteria, body fluids and sera, blood clots, dead or necrotic tissue, and the like. Treatment of an abscess entails debriding the abscess and draining it of such materials contained in it.
A variety of suction and other devices are known for cutting and removing a wide range of materials from the body at locations other than abscesses. Such devices usually possess a structure which is particularly adapted to the location of interest, and which is particularly adapted to the material to be removed. Unfortunately, such devices are ill-suited to the particular problems encountered when draining and debriding abscesses. More particularly, such devices are generally rigid and are therefore not suited for introduction into and through an existing tract or passage in which an abscess has formed.
For example, U.S. Pat. No. 4,660,267 (C. R. Wheeler, Apr. 28, 1987) discloses a method of fabricating a surgical probe for performing arthroscopic surgery. The probe resulting from the method includes an outer tube and an inner tube which rotates at relatively high speeds within the outer tube. A bearing is formed by an inwardly extending bearing surface on the distal end of the outer tube and a complementary bearing surface on the distal end of the inner tube. Each of the outer and inner tubes has aligned openings on one side near their distal ends, such that the high speed rotation of the inner tube within the outer tube shaves tissue entering the side openings. Suction is applied to the inner tube to draw the shaved tissue away from the distal end of the probe to avoid clogging of the openings. The bearing provides both radial and longitudinal thrust bearing support to the device during rotation of the inner tube.
U.S. Pat. No. 5,295,980 (R. A. Ersek, Mar. 22, 1994) is directed to an infusion and aspiration catheter useful, for example, during liposuction or a biopsy, which includes a cannula member having a rounded, partially open, blunt insertion tip, and a stilette (sic., presumably a stylet) which is received in the cannula member. The stilette can be rotated or moved longitudinally in the cannula member to cut, saw or grasp a tissue specimen. The patent notes at column 5, lines 5 through 10, that it is important that the opening of the cannula member be located on a taper between the blunt end of the member and the cylindrical shaft portion of the member, but that the opening encompass neither the distal end nor any portion of the shaft of the member.
U.S. Pat. No. 5,290,303 (E. D. Pingleton, Mar. 1, 1994) discloses a surgical cutting instrument for laparoscopic or endoscopic use which includes an inner rotary tube member having a cutting edge at its distal end which extends from a stationary sheath which prevents tissue from wrapping around the rotary tube member. The inner cutting member tube includes a hollow passageway for suctioning and aspirating tissue and fluid, and the instrument further includes an outer safety shield having a rounded distal end for preventing puncture of a surgical tissue bag, or for preventing the unintentional cutting of tissue. An access channel for accepting tissue is located laterally about the distal end of the safety tube, and acts as a jaw which feeds tissue into a rotary cutting edge extending circumferentially about the distal end of the inner member.
Finally, U.S. Pat. No. 4,655,743 (L. L. Hyde, Apr. 7, 1987) is directed to an irrigation-aspiration device useful in eye surgery and which includes an outer cannula and an inner cannula which can be reciprocated within the outer cannula. Tissue is drawn into the device through a lateral suction port located proximal to the distal tip of the inner cannula, and is cut between the suction port and the distal tip of the outer cannula. The inner cannula is bent along its length and is springy so that the port abrades against the end of the outer cannula with a biting or cutting action. An inner lumen of the inner cannula is connected to vacuum or a suction source to draw fragments of the eye into the port for cutting.
While these devices appear to be useful for their individual and particularly intended purposes, it would appear that none of these devices is particularly adapted for debriding and draining an abscess, phlegmon, or hematoma, and that none of these devices is capable of performing not only their individual and particularly intended purposes, but also the additional functions of a conventional drainage catheter. In particular, substantially all of these devices include a rigid first cutting cannula inside a rigid second cutting cannula. Such devices are not intended to be left in a patient to allow drainage of a site of interest, for example, an abscess, after performing one surgical technique or another.
It would be highly desirable to have a debriding device which was particularly adapted for debriding and draining an abscess or phlegmon in a human or veterinary patient, and which was structured to meet the particular problems encountered in debriding and draining an abscess. It would also be highly advantageous to have such a device which was sufficiently flexible to allow it to be introduced into and through any existing tract in which an abscess has developed. It would further be advantageous to have such a device in which it is primarily the cutting cannula which shears any tissue or other material to be debrided, in contrast to the more rigid prior devices in which the stiffness of an outer cannula contributes substantially to the shearing of such tissue or other material. It would be still further advantageous to have such a device which was capable of cutting blood clots and dead or necrotic tissues in or adjacent to the abscess, and which was capable of removing, by suction, any materials so cut. Finally, it would also be highly desirable to have such a device which could be left in a patient for some time after the performance of a surgical technique, for draining the site at which the technique was performed.
The foregoing problems are solved and a technical advance is achieved in an illustrative medical device particularly adapted for debriding and draining abscesses present in a human or veterinary patient. The device of the present invention is directed to a specific combination which either comprises or consists of a catheter having a lateral opening, and a cutting needle or cannula (hereinafter, xe2x80x9ccutting cannulaxe2x80x9d) received in the catheter and having a circumferential cutting edge which can be slid along the lateral opening of the catheter. Longitudinal movement of the cutting cannula in the catheter causes the circumferential cutting edge to sever any material which extends through the lateral opening. Suction is applied to the proximal end of the cutting cannula to draw material from the abscess through the lateral opening of the catheter, through the cutting cannula and out of the device. The catheter is preferably flexible and is adapted to allow drainage of the abscess even when the cutting cannula is not positioned in the catheter.
This specific cutting structure is quite different from the prior devices mentioned above, which have been employed for decidedly different purposes. First, the prior devices mentioned above generally include a first rigid cutting cannula inside a second rigid cutting cannula. The present invention, in contrast, includes a catheter as its outer member. The use of the catheter in the present invention allows the device of the present invention to not only debulk the abscess, but also to remain in position and drain the abscess after debriding has been carried out with the present device. Second, the circumferential cutting edge on the cutting cannula makes the cutting cannula a front-cutting needle, rather than a side-cutting needle as is employed in many of the prior devices mentioned above. Because of this, the tissue to be debrided is sheared mainly by the cutting cannula itself; the lateral opening (in conjunction with any applied suction) merely holds the tissue in place, rather than actively contributing to shearing of the tissue. The first of these differences, that is, the use of a catheter in the device instead of a rigid cannula, is probably the more important with regard to the good utility enjoyed by the present invention.
In a first aspect, then, the present invention is directed to a medical device particularly adapted for debriding an abscess in a human or veterinary patient, for removing debrided and other materials from the abscess and for draining the abscess, comprising: a catheter having a longitudinally extending flow lumen defined therein, a distal tip closing the flow lumen, a side portion extending proximally from the distal tip and a lateral opening formed in and extending through the side portion; and a cutting cannula positionable in and longitudinally slidable in the flow lumen in the catheter, having an open distal end and a circumferential cutting edge formed on the open distal end, the circumferential cutting edge moving across the lateral opening of the catheter upon longitudinal sliding movement of the cutting cannula in the flow lumen of the catheter and thereby cutting any material extending from the abscess and through the lateral opening of the catheter.
Preferably, the circumferential cutting edge of the cutting cannula is sharp and beveled from the outer surface to inner surface. Alternatively, the cutting edge can be beveled from the inner to the outer surface (countersunk). The circumferential cutting edge of the cutting cannula is disposed perpendicularly to the flow lumen of the catheter. The cutting cannula is preferably composed of a stainless steel circumferentially ground needle cannula, although tetrafluoroethylene, polyethylene terephthalate, or any other suitable medical grade material can be used.
The distal tip of the catheter is preferably rounded, and the lateral opening of the catheter can be oval in shape or otherwise shaped as convenient. The lateral opening can extend about one third of the way around the catheter and about 5 to 6 mm along the direction of the flow lumen. The catheter is adapted for introduction to the abscess and drainage of the abscess even when the cutting cannula is not positioned in the flow lumen of the catheter. The catheter is preferably about 10-16 French (3-5 mm) in diameter and about 33 cm long, and can be composed of vinyl non-radiopaque tubing, a urethane tubing such as USI Petrothane, or another appropriate flexible medical grade material.
The debriding device of the present invention preferably further comprises a suction source connectable to the proximal end of the cutting cannula for withdrawing any materials cut by the circumferential cutting edge of the cutting cannula, as well as any other materials contained in the abscess, phlegmon, or hematoma. The device preferably further comprises a seal element located adjacent to the proximal end of the catheter, through which the cutting cannula can be passed. The device can still further comprise a side arm in fluid communication with the flow lumen of the catheter, connected to the proximal end of the catheter by a fitting containing the seal element.
In a second aspect, the present invention is directed to a medical device particularly adapted for debriding an abscess in a human or veterinary patient, for removing debrided and other materials from the abscess and for draining the abscess, comprising: a flexible catheter having a longitudinally extending flow lumen defined therein, a rounded distal tip closing the flow lumen, a side portion extending proximally from the distal tip and an oval lateral opening formed in and extending through the side portion; and a cutting cannula positionable in and longitudinally slidable in the flow lumen in the catheter, having an open distal end and a sharp, beveled circumferential cutting edge formed on the open distal end, the circumferential cutting edge being disposed perpendicularly to the flow lumen of the catheter and moving across the oval lateral opening of the catheter upon longitudinal sliding movement of the cutting cannula in the flow lumen of the catheter and thereby cutting any material extending from the abscess and through the lateral opening of the catheter; wherein the cutting cannula further has a proximal end opposite the open distal end adapted for the application of suction thereto; wherein the catheter is adapted for introduction to the abscess and drainage of the abscess when the cutting cannula is not positioned in the flow lumen of the catheter; wherein the catheter is about 10-16 French (3-5 mm) in diameter and is about 33 cm long; wherein the catheter further has a proximal end opposite the distal tip, and wherein the device further comprises a seal element located adjacent to the proximal end of the catheter through which the cutting cannula can be passed; wherein the lateral opening of the catheter extends about one third of the way around the catheter and extends about 5 to 6 mm along the direction of the flow lumen; and wherein the device further comprises a side arm connected to the proximal end of the catheter in fluid communication with the flow lumen of the catheter and a fitting connecting the side arm to the proximal end of the catheter, the seal element being contained in the fitting.
In a final aspect, the present invention is directed to a medical device particularly adapted for debriding an abscess, phlegmon, or hematoma in a human or veterinary patient, for removing debrided and other materials from the abscess and for draining the abscess, consisting of: a flexible catheter having a longitudinally extending flow lumen defined therein, a rounded distal tip closing the flow lumen, a side portion extending proximally from the distal tip and an oval lateral opening formed in and extending through the side portion; and a cutting cannula positionable in and longitudinally slidable in the flow lumen in the catheter, having an open distal end and a sharp, beveled circumferential cutting edge formed on the open distal end, the circumferential cutting edge being disposed perpendicularly to the flow lumen of the catheter and moving across the oval lateral opening of the catheter upon longitudinal sliding movement of the cutting cannula in the flow lumen of the catheter and thereby cutting any material extending from the abscess and through the lateral opening of the catheter; wherein the cutting cannula further has a proximal end opposite the open distal end adapted for the application of suction thereto; wherein the catheter is adapted for introduction to the abscess and drainage of the abscess when the cutting cannula is not positioned in the flow lumen of the catheter; wherein the catheter is about 10-16 French (3-5 mm) in diameter and is about 33 cm long; wherein the catheter further has a proximal end opposite the distal tip, and wherein the device further consists of a seal element located adjacent to the proximal end of the catheter through which the cutting cannula can be passed; wherein the lateral opening of the catheter extends about one third of the way around the catheter and extends about 5 to 6 mm along the direction of the flow lumen; and wherein the device further consists of a side arm connected to the proximal end of the catheter in fluid communication with the flow lumen of the catheter and a fitting connecting the side arm to the proximal end of the catheter, the seal element being contained in the fitting.
The abscess debriding device of the present invention possesses several significant advantages. It is capable of cutting blood clots and dead or necrotic tissues in or adjacent to the abscess and is capable of removing, by suction applied to the cutting cannula, any materials so cut. The catheter of the device is sufficiently flexible to allow the device to be introduced into and through a tract in which an abscess has developed. The catheter of the device is also sufficiently flexible to further allow the device to be left in a patient for some time after the performance of a surgical technique, for draining the site at which the technique was performed. The abscess drainage device of the present invention is particularly adapted for all of these tasks, not just debriding as is the case with prior devices, and is structured to meet the particular problems encountered during debriding and draining an abscess, phlegmon, or hematoma. Advantageously, in the device of the present invention it is primarily the cutting cannula which shears the tissue or other material to be debrided, in contrast to the more rigid prior devices in which the stiffness of an outer cannula contributes substantially to the shearing of such tissue or other material.